SULPHAMIDE FROM AMMONIUM AMIDOSÜLPHITE. O 



sulpliate, left with the sulphamide, may cause a little difficulty, 

 unless care be taken. 



On referring to the memoir on amidosulphuric acid in the 

 Journal of the College of Science for 1896 (9, 239-241, "amido- 

 sulphonic acid "), it will be found there stated that when an 

 alkali is added in suitable quantity to a solution of mixed silver 

 nitrate and potassium amidosulphate, a bright yellow, amorphous 

 salt is precipitated, which is very probably AgHN.S0 3 .K, and is 

 soluble in and ultimately decomposed by excess of alkali. It is 

 now found that, in precipitating silver sulphamide in presence of 

 ammonium amidosulphate, as in the present case, a very small 

 quantity of a bright-yellow substance, probably ammonium argent- 

 amidosulphate, is apt to accompany the silver sulphamide, and 

 that, in order to circumvent this liability and, at the same time, 

 to avoid loss of the silver sulphamide through its solubility in 

 ammonia in presence of ammonium nitrate, precipitation should 

 be carried out in the following way. Having added more silver 

 nitrate, dilute ammonia is dropped in, slowly and with stirring, 

 until the solution is slightly alkaline. The precipitate is quickly 

 filtered off and washed free from mother-liquor. The solution is 

 again treated with silver nitrate and ammonia, as before, in order 

 to see whether any more sulphamide is thrown down. This being 

 quickly filtered off, if it be desired to obtain a sight of the 

 yellow compound, a few drops of ammonia may be added, and 

 dilute silver nitrate very slowly dropped in, when it will be 

 produced. 



The silver sulphamide, perhaps a little yellow after all, is 

 to be dissolved in dilute nitric acid, ammonia added to slight 

 alkalinity, as before, and then two or three drops of silver nitrate. 

 After a repetition of this treatment, the precipitate is stirred up 



